Low temperature growth of Ga2O3 thin films on Si substrates by MOCVD and their electrical characteristics

Ga2O3 thin films were grown on n-type Si substrates at various growth temperatures of 500, 550, 600, 650 and 700 degrees C. The Ga2O3 thin films grown at 500 degrees C and 550 degrees C were characterized as featureless flat surface. Grown at higher temperatures (600, 650, and 700 degrees C) showed very rough surface morphology. To figure out the annealing effect on the thin films grown at relatively low temperatures (500, 550, 600, 650 and 700 degrees C), the Ga2O3 films were thermally treated at 900 degrees C for 10 minutes. Crystal structure of the Ga2O3 films grown at 500 and 550 degrees C were changed from amorphous to polycrystalline structure with flat surface. Ga2O3 film grown at 550 degrees C was chosen for the fabrication of a Schottky barrier diode (SBD). Electrical properties of the SBDs depend on the thermal treatment were evaluated. A MSM type photodetector was made on the low temperature grown Ga2O3 thin film. The photocurrent for the illumination of 266 nm wavelength showed 5.32 times higher than dark current at the operating voltage of 10 V.